Thermoelectric materials are used in the manufacture of such items as refrigerators, heaters and generators. It is desirable for these thermoelectric materials to have large Seebeck coefficients, as defined herein below, and have high electrical conductivity but low thermal conductivity. The performance of thermoelectric conversion materials is expressed as “Figure of Merit (ZT)”. At present, the best thermoelectric materials have ZT values of about 1.0.
Akai et al, Proceedings of the 17th International Conference on Thermoelectrics, 1998, 105-108 characterize Indium-doped Cobalt Antimonide produced by a solid phase reaction followed by hot-pressing.
In contrast, the process of the present invention uses firing of mixed powder in 1 to 15% hydrogen and 85 to 99% argon followed by a furnace cool. The calcined powder is then reground and pressed into disks which are then sintered at 675° C. for 4 hours in the same hydrogen/argon mixture. This procedure can result in material with a ZT greater than 1.0.